.TT pocketengineer building services engineering - pipe & duct thermal insulation

.TT pocketengineer building services engineering

Pipe & Duct thermal insulation calculations software

Pipe or Duct Insulation Calculation (pocketINSUL)

calculate insulation thickness, heat gain for duct and pipe

To take a glance at all pocketEngineer software and OS requirements, click Software List.

pocketINSUL: insulation thickness calculator

pocketINSUL is a small program for duct & pipe insulation thickness calculations including heat gain. It is designed as portable mobile app for Windows desktop/laptop PC.

Aim: creating a mobile design environment (ShowMe!) for the practising engineers & designers in today's mobile world.

Results: Instant solutions at your fingertips.

Highlights:

calculate insulation thickness and Heat gain for cold duct, cold pipe & hot pipe
embedded data - just "select & click"
results "save-to-file" for printing
in SI & IP units

Note: This software can only perform calculation for a single layer of insulation material.

Why need insulation . . .

Apart from preventing heat gain or loss for energy conservation, the first principle of having insulation is to:

prevent surface condensation for cold application. Condensation will occur if the surface temperature falls below the dew point temperature of the surrounding conditions.
provide safe "touch" surface for hot application. As a guide, it is recommended to keep the safe "touch" temperature to below 60 oC (140 oF).

pocketINSUL is designed with flexibility in mind. It goes beyond the main purpose of just finding insulation thickness required. pocketINSUL can also be used to calculate whether surface condensation will occur or not for a given insulation thickness. This is done by comparing the calculated surface temperature against the dew point temperature. This comes handy when you need to perform condensation analysis for cold pipe or duct condensation problem.

Note: The calculation adopted in pocketINSUL has ignored the thermal resistivity due to the pipe material wall. For metal pipe, it practically offers no resistance to heat flow. For non-metal pipe, the calculated result would err on the safe side.

Example 1: Condensation Analysis for Chilled-Water Pipe (in SI Units)

Input parameters are as follows:

chilled-water temperature = 6 oC
steel pipe OD = 114.3 mm
insulation thermal conductivity = 0.023 W/m.K
surface air film coefficient = 0.175 m2K/W

The following table shows the condensation analysis for insulation thickness of 25 mm.

The following table shows the condensation analysis for insulation thickness of 50 mm.

Example 2: Chilled Water Pipe insulation (in SI Units)

A 100mm diameter (OD=114.3mm) steel pipe carrying 6.7 oC chilled water runs through a plant room at an indoor condition of 30 oC, 95% RH. The pipe is to be insulated with polyurethane foam, 48 kg/m3 insulation material of thermal conductivity of 0.023 W/moK, and protected by polished aluminium cladding. Determine the minimum insulation thickness required.

The following results are obtained by pocketINSUL program:

Cold Pipe Insulation calculations

[1] Ambient Conditions:-

Temperature=30 oC

RH=95 %

Dewpoint Temp=29.10 oC

[2] Surface Air Film:-

Outer Surface=0.175 m2K/W

[3] Inside Pipe:-

Fluid Temp=6.7 oC

[4] Bare Pipe:-

Outer Diameter=114.3 mm

[5] Insulation:-

Conductivity=0.023 W/mK

Min. Thickness=69.00 mm

Surface Temp=29.10 oC

.........

Recommended min. thickness=81.00 mm

Surface Temp=29.26 oC

.........

[6] Heat Gain Calculation:-

Insulation thickness=81.00 mm

Heat gain=3.69 W/m run

Heat gain=4.25 W/m2

Surface temperature=29.26 oC

Example 3: Hot Pipe insulation for process water (in SI Units)

A 400mm diameter steel pipe (OD=406.4mm) carrying a hot process fluid of 454 oC needs to be insulated for safety reason. The recommended safe "touch" temperature is 54.4 oC. The ambient temperature is 29.4 oC. Calcium silicate with thermal conductivity of 0.06 W/moK is used for the pipe insulation. Determine the minimum insulation thickness required.

The following results are obtained by pocketINSUL program:

Hot Pipe Insulation calculations

[1] Ambient Conditions:-

Temperature=29.4 oC

[2] Surface Air Film:-

Outer Surface=0.125 m2K/W

[3] Inside Pipe:-

Fluid Temp=454 oC

[4] Bare Pipe:-

Outer Diameter=406.4 mm

[5] Insulation:-

Conductivity=0.060 W/mK

Insulation Thickness =99.00 mm

Casing Temperature =54.4 oC

[6] Heat Gain Calculation:-

Heat gain =-200.00 W/m2

Heat gain =-379.76 W/m run

Note: -ve sign denotes Heat Loss.

Example 4: Change air-conditioning Duct insulation at job site due to site constraint (in IP units)

An air-conditioning air duct carrying 55 oF cold air needs to be diverted to the outdoor canopy due to site constraint. The design outdoor condition is 80 oF and 95% RH for rainy/humid day. The air duct is wrapped with 32 kg/m3 insulation material of thermal conductivity of 0.236 Btu.in/hr.ft².F, and protected by polished aluminium cladding. Find the new insulation thickness required.

The following results are obtained by pocketINSUL program:

Cold Duct Insulation calculations

[1] Ambient Conditions:-

Temperature=80 oF

RH=95 %

Dewpoint Temp=78.4 oF

[2] Surface Air Film:-

Outer Surface=0.994 hr.ft².F/Btu

Inner Surface=0.250 hr.ft².F/Btu

[3] Inside Duct:-

Air Temp=55 oF

[4] Insulation:-

Conductivity=0.236 Btu.in/hr.ft².F

Min. Thickness=3.50 in

Surface Temp=78.45 oF

.........

Recommended min. thickness=3.97 in

Surface Temp=78.63 oF

.........

[5] Heat Gain Calculation:-

Insulation thickness=3.97 in

Heat gain=1.38 Btu/hr.ft²

Surface temperature=78.63 oF

Example 5: PEX Pipe for hot water (in IP Units)

Do we really need insulation for PEX tubing for hot water service?

Given a 1 inch diameter PEX tubing with the following data:

ID = 0.863 in.
wall thickness = 0.125 in.
conductivity = 2.86 Btu.in/hr.ft².F

We analyse the bare pipe surface (casing) temperature and its heat loss.

The following results are obtained by pocketINSUL program:

Hot Pipe Insulation calculations

[1] Ambient Conditions:-

Temperature=82 oF

[2] Surface Air Film:-

Outer Surface=0.568 hr.ft².F/Btu

[3] Inside Pipe:-

Fluid Temp=140 °F

[4] Bare Pipe:-

Outer Diameter=0.863 in

(note: ID is used here)

[5] Insulation:-

Conductivity=2.86 Btu.in/hr.ft².F

Insulation Thickness =0.125 in

(note: insulation thickness is the wall thickness of PEX tubing)

Casing Temperature =135.35 °F

[6] Heat Gain Calculation:-

Heat gain =-93.92 Btu/hr.ft²

Heat gain =-27.37 Btu/hr.ft run

Note: -ve sign denotes Heat Loss.

pocketINSUL

Cold Duct Insulation module

Cold Pipe Insulation Module

Hot Pipe Insulation module

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For Surface Condensation calculation, see to Hello! Condensation (Android program).

For U-value + Condensation prediction, see U-value calculator (Windows program).

Pay & instant Download via PayPal Digital Goods service:

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pocketINSUL

Price: US $9.90

OS requirements: Windows

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